1. Field of the Invention
The present invention relates to an image processing device and an electronic apparatus. More particularly, the invention relates to an image processing device and electronic apparatus which are suitable for detecting the shape of a hand of a person or the like, for example, in an image obtained by imaging the object.
2. Description of the Related Art
In the related art, there are skin recognition systems which detect (recognize) a skin area representing the skin of a person in an image obtained by imaging an object (for example, see Yasuhiro Suzuki et al. “Proposal on Skin Detection by Near Infrared Multi-Band”, IEEJ Transactions C, No. 4, Volume 127, 2007, Japan (Non-Patent Document 1)).
FIG. 1 shows an exemplary configuration of a skin recognition system 1 according to the related art.
The skin recognition system 1 includes a light source section 21, a camera 22, and an image processing section 23.
The light source section 21 includes LEDs (light-emitting diodes) 21 a each radiating (emitting) light having a wavelength λ1 (e.g., near infrared light having a wavelength of 950 [nm]) which are represented by ten dots and LEDs 21b each radiating light having a wavelength λ2 different from the wavelength λ1 (e.g. near infrared light having a wavelength of 870 [nm]) which are represented by ten white circles.
The wavelengths λ1 and λ2 are combined such that the light of the wavelength λ1 has a reflectance lower than that of the light of the wavelength λ2 when those light rays are projected on human skin and such that the light rays having the respective wavelengths λ1 and λ2 are reflected at substantially the same reflectance when projected on an object other than human skin.
The LEDs 21a and the LEDs 21b are disposed so as to form a checkerboard pattern to emit light, for example, in an alternate manner.
The camera 22 images an object illuminated by the light of the wavelength λ1 from the LEDs 21a and images an object illuminated by the light of the wavelength λ2 from the LEDs 21b. The camera supplies each of the images thus imaged to the image processing section 23.
Specifically, the camera 22 receives a reflected light ray, i.e., the light of the wavelength λ1 emitted by the LEDs 21a and reflected by an object and supplies a first image thus imaged to the image processing section 23. The camera 22 also receives another reflected light ray, i.e., the light of the wavelength λ2 emitted by the LEDs 21b and reflected by the object and supplies a second image thus imaged to the image processing section 23.
The image processing section 23 calculates absolute differences between luminance values of pixels corresponding between the first and second images imaged by the camera 22 and detects a skin area in the first image (or the second image) based on the calculated absolute differences.
The reflectance at which the light of the wavelength λ1 is reflected on human skin is lower than the reflectance at which the light of the wavelength λ2 is reflected on human skin. Therefore, the luminance values of the pixels forming a skin area in the first image are relatively small, and the luminance values of the pixels forming the skin area in the second image are relatively great.
Therefore, absolute differences between the luminance values of the pixels forming the skin area in the first and second images have relatively great values. The reflectance at which the light of the wavelength λ1 is reflected on an object other than human skin is substantially the same as the reflectance at which the light of the wavelength λ2 is reflected on the object other than human skin. Therefore, the luminance values of the pixels forming an area of the first image other than the skin area are substantially the same as the luminance values of the pixels forming the area of the second image other than the skin area.
Thus, absolute differences between the luminance values of the pixels forming the area in the first and second images other than the skin area have relatively small values.
Therefore, the image processing section 23 of the skin recognition system 1 can detect an area of interest as a skin area, for example, when absolute differences as thus described have relatively great values.
Thus the skin recognition system 1 can detect the skin area of the first image based on the first and second images obtained by imaging the object.
For example, when the skin recognition system 1 is incorporated in a television receiver, a hand of a user can be detected, and a gesture of the user associated with a predetermined operation can be recognized from the result of the detection. Further, an operation such as changing a selected channel can be carried out based on what is recognized.